The advancement of generative artificial intelligence (AI) presents innovative opportunities and new challenges across various industries and academic fields. Particularly, recent advancements in generative AI, which can create images from text, are introducing new challenges in the field of graphic design education. This study discusses methods of graphic design education utilising generative AI, based on workshops conducted in the "Visual Culture and Contemporary Art" course in the first semester of 2023. Students utilised generative AI, such as Midjourney and DALL-E, based on the "Technology Pedagogical Content Knowledge (TPCACK)" model, to create posters depicting European design history. Through the analysis of case studies and survey results, researchers confirmed that graphic design education in the era of generative AI requires different educational goals and methods from those of traditional education. Students require AI visual literacy skills to accurately convey images using suitable keywords. Additionally, it was discovered that preliminary design processes such as trend analysis and research have become more crucial. Additionally, educators should provide students with opportunities to derive creative keywords through graphic storytelling and present a vision as content creators who combine science, art, and technology. This research provides guidelines for the roles of graphic designers and the direction of visual design education in the era of generative AI.